Do not store StackTrace type

Author: alichraghi

src/Sema.zig

@@ -9785,6 +9785,8 @@ fn finishFunc(
     const zcu = pt.zcu;
     const ip = &zcu.intern_pool;
     const gpa = sema.gpa;
+    const target = zcu.getTarget();
+    const backend = target_util.zigBackend(target, zcu.comp.config.use_llvm);
 
     const return_type: Type = if (opt_func_index == .none or ret_poison)
         bare_return_type
@@ -9911,13 +9913,11 @@ fn finishFunc(
         }),
     }
 
-    if (!is_generic and sema.wantErrorReturnTracing(return_type)) {
+    if (backend == .stage2_llvm and !is_generic and sema.wantErrorReturnTracing(return_type)) {
         // Make sure that StackTrace's fields are resolved so that the backend can
         // lower this fn type.
         const unresolved_stack_trace_ty = try sema.getBuiltinType(block.nodeOffset(.zero), .StackTrace);
         try unresolved_stack_trace_ty.resolveFields(pt);
-
-        if (zcu.stack_trace_type == .none) zcu.stack_trace_type = unresolved_stack_trace_ty.toIntern();
     }
 
     return Air.internedToRef(if (opt_func_index != .none) opt_func_index else func_ty);

src/Zcu.zig

@@ -308,7 +308,6 @@ free_type_references: std.ArrayListUnmanaged(u32) = .empty,
 
 /// Populated by analysis of `AnalUnit.wrap(.{ .memoized_state = s })`, where `s` depends on the element.
 builtin_decl_values: BuiltinDecl.Memoized = .initFill(.none),
-stack_trace_type: InternPool.Index = .none,
 
 incremental_debug_state: if (build_options.enable_debug_extensions) IncrementalDebugState else void =
     if (build_options.enable_debug_extensions) .init else {},

src/codegen/llvm.zig

@@ -2596,7 +2596,8 @@ pub const Object = struct {
                 }
 
                 if (fn_info.cc == .auto and zcu.comp.config.any_error_tracing) {
-                    const ptr_ty = try pt.ptrType(.{ .child = zcu.stack_trace_type });
+                    const stack_trace_ty = zcu.builtin_decl_values.get(.StackTrace);
+                    const ptr_ty = try pt.ptrType(.{ .child = stack_trace_ty });
                     debug_param_types.appendAssumeCapacity(try o.lowerDebugType(pt, ptr_ty));
                 }
 
@@ -3508,7 +3509,8 @@ pub const Object = struct {
         }
 
         if (fn_info.cc == .auto and zcu.comp.config.any_error_tracing) {
-            const ptr_ty = try pt.ptrType(.{ .child = zcu.stack_trace_type });
+            const stack_trace_ty = zcu.builtin_decl_values.get(.StackTrace);
+            const ptr_ty = try pt.ptrType(.{ .child = stack_trace_ty });
             try llvm_params.append(o.gpa, try o.lowerType(pt, ptr_ty));
         }